Glabrous, preserving through life the habit of the first-year seedling of Dioscorea, which lies in the arrest of the second leaf of a stem to the advantage of the first. In the surface soil a rather dry, 1-4 cm long rhizome with occasional branching, ascending slightly at the apex and dying behind, losing its scale-like leaves before death, coated with chaffy very acute scale-leaves up to 5 mm long. Stems 5-7(-20), erect or ascending, to 12 cm below the solitary leaf, with c. 7 low ridges. Fertile branch with distichous scale-leaves similar to those on the rhizome but shorter, with flower buds in their axils, the whole looking like a spikelet of Brornus. Flowers extruded from between the protecting scale-leaves one at a time until 1 or 2 are pollinated whereupon those following are arrested. Leaf (in Malaysia) always cordate-sagittate, 10 by 4 cm, primary nerves 5-7, 3 reaching the blunt apex, the outer being in the margin. Blade shortly acuminate below the apex; margin undulate; petiole usurping the line of the stem by pushing the fertile branch to one side, vertical (in Malaysia). Pedicels to 7 cm long, nodding, dull purple with a greenish colour towards the base. Tepals (in Malaysia) to 1 cm long. Stamens 6, anthers raised on short zigzag filaments widening into broad connectives with the anthers edge to edge and making a roof over a chamber into which pollinating insects should enter; beyond the anthers the filament is prolonged into a process which projects forwards between the stigmas. Style stout. Fruit 3-winged, wings thick instead of flat as in Dioscorea, to 13 by 6 mm, somewhat trapezoid by reason of the way in which they narrow towards the apex and the base of the fruit, broadest above mid-length. Seeds upwards of 6 freed by the fruit walls breaking irregularly, wingless, flat, more so on one side than on the other, and differently invaginated.
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